pgbench: fix misprocessing of some nested \if constructs.

An \if command appearing within a false (not-to-be-executed) \if
branch was incorrectly treated the same as \elif.  This could allow
statements within the inner \if to be executed when they should
not be.  Also the missing inner \if stack entry would result in an
assertion failure (in assert-enabled builds) when the final \endif
is reached.

Report and patch by Michail Nikolaev.  Back-patch to all
supported branches.

Discussion: https://postgr.es/m/CANtu0oiA1ke=SP6tauhNqkUdv5QFsJtS1p=aOOf_iU+EhyKkjQ@mail.gmail.com

diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index 47467c32dd8b96159364c5de3dd3e3eda1623538..36282a99bb6114e5302ee878bdeae89a2ba9826c 100644 (file)
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -3879,8 +3879,14 @@ advanceConnectionState(TState *thread, CState *st, StatsData *agg)
                        switch (conditional_stack_peek(st->cstack))
                        {
                            case IFSTATE_FALSE:
-                               if (command->meta == META_IF ||
-                                   command->meta == META_ELIF)
+                               if (command->meta == META_IF)
+                               {
+                                   /* nested if in skipped branch - ignore */
+                                   conditional_stack_push(st->cstack,
+                                                          IFSTATE_IGNORED);
+                                   st->command++;
+                               }
+                               else if (command->meta == META_ELIF)
                                {
                                    /* we must evaluate the condition */
                                    st->state = CSTATE_START_COMMAND;
@@ -3899,11 +3905,7 @@ advanceConnectionState(TState *thread, CState *st, StatsData *agg)
                                    conditional_stack_pop(st->cstack);
                                    if (conditional_active(st->cstack))
                                        st->state = CSTATE_START_COMMAND;
-
-                                   /*
-                                    * else state remains in
-                                    * CSTATE_SKIP_COMMAND
-                                    */
+                                   /* else state remains CSTATE_SKIP_COMMAND */
                                    st->command++;
                                }
                                break;

diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 956e290f3efab9877ac575a0d74b3c3ee6661f1a..65ffa4468f30e66f624f5c5ef8b7aee2d3f46efb 100644 (file)
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -668,6 +668,56 @@ SELECT :v0, :v1, :v2, :v3;
 }
    });
 
+# test nested \if constructs
+$node->pgbench(
+   '--no-vacuum --client=1 --exit-on-abort --transactions=1',
+   0,
+   [qr{actually processed}],
+   [qr{^$}],
+   'nested ifs',
+   {
+       'pgbench_nested_if' => q(
+           \if false
+               SELECT 1 / 0;
+               \if true
+                   SELECT 1 / 0;
+               \elif true
+                   SELECT 1 / 0;
+               \else
+                   SELECT 1 / 0;
+               \endif
+               SELECT 1 / 0;
+           \elif false
+               \if true
+                   SELECT 1 / 0;
+               \elif true
+                   SELECT 1 / 0;
+               \else
+                   SELECT 1 / 0;
+               \endif
+           \else
+               \if false
+                   SELECT 1 / 0;
+               \elif false
+                   SELECT 1 / 0;
+               \else
+                   SELECT 'correct';
+               \endif
+           \endif
+           \if true
+               SELECT 'correct';
+           \else
+               \if true
+                   SELECT 1 / 0;
+               \elif true
+                   SELECT 1 / 0;
+               \else
+                   SELECT 1 / 0;
+               \endif
+           \endif
+       )
+   });
+
 # random determinism when seeded
 $node->safe_psql('postgres',
    'CREATE UNLOGGED TABLE seeded_random(seed INT8 NOT NULL, rand TEXT NOT NULL, val INTEGER NOT NULL);'